X-ray diagnostic systems are standard medical imaging equipment and are used e.g. for interventional therapy. Angiographic systems, generally C-arm X-ray systems, are typically used for monitoring vascular and heart disease therapy and for minimally invasive tumor therapy. Their flat-panel X-ray detectors with pixel elements disposed in a matrix provide a very high local resolution (pixel size generally about 150 μm) and can be used for both for 2D and 3D imaging (Siemens DynaCT). In 3D imaging, however, the conventional CT machines are still superior in terms of low-contrast resolution and imaging speed; in 2D imaging, on other hand, they have disadvantages in terns of the resolution and scan field.
To utilize the advantages of both systems, an X-ray diagnostic apparatus is known e.g. from DE 198 02 405 B4 wherein two imaging systems are disposed on a rotating gantry, a CT imaging system with a line scan X-ray detector and an angiographic imaging system with a large area X-ray detector. With the CT imaging system, the known CT modalities can be implemented, e.g. the taking of sequential slices using so-called stop-and-shoot movement of a patient table or helical imaging with continuous movement of the patient table and continuous gantry rotation. With the angiographic imaging system, two known modalities can be implemented: 2D fluoroscopic imaging with stationary gantry and 3D rotational imaging (e.g. DynaCT) with continuously or sequentially rotating gantry.